If I were you (op) I would reflash stock, copy everything to PC (all apps/apks) and slowly remove a few at a time and test gps as I go along. I know that would take some time but eventually you would find which ones have to do with gps. You could also make a list of all the names of the apks and throw them in your "search" on a browser and see what all you can find out about them that way..
The most detailed explanation I have ever seen of descriptions of apps is definitely xXx No Limit magisk rom for OnePlus 6,7,8 devices. The dev has a user configuration file where you choose whether you want to keep, delete, replace each apk in the entire device and he has an explanation for every single app that tells what it's used for and if it's safe to delete or not. I would search all I could, and maybe do the copy/delete apk first and see what all you can find then maybe shoot No Limit rom dev a msg asking him. IDK him personally except from here using his rom when I had a OnePlus 6t but I bet he would respond. Most people will help you out "if" they can see whoever is asking for the help has already done some work in to whatever it is themselves.
